The storm track and mean flow patterns associated with the midwinter
suppression and interannual variability of the Pacific storm track are
identified using NCEP Reanalysis data from 1979 to present. Cross
spectrum analysis is used to investigate whether these patterns exist on
subseasonal timescales in midwinter, and to determine the lead-lag
relationship between storm track and mean flow anomalies on subseasonal
timescales. The PNA-like mean flow pattern associated with interannual
variability appears to dominate variability at a period of 60 days, but
not 20 days, while the midwinter suppression mean flow pattern does not
appear important at any subseasonal timescale. The interannual storm
track pattern appears to lead the interannual PNA-like mean flow pattern
by 2-4 days at a period of 20 days, while the patterns are approximately
simultaneous at a period of 60 days. It is suggested that the patterns of
interannual variability are more likely to be an example of coupled
eddy-mean flow variability, while midwinter suppression is primarily
externally forced. The tropical precipitation patterns associated with
midwinter suppression and interannual variability are shown to motivate
future work on the forcing of the midlatitude storm track-mean flow system
by tropical convection.